Viggo Mortensen was dubbed 'Summer Dad' on Captain Fantastic

Viggo Mortensen has revealed his child co-stars on 'Captain Fantastic' gave him the name 'Summer Dad' due to the close bond they developed when shooting the family drama

Viggo Mortensen was dubbed 'Summer Dad' by his young co-stars on his new movie 'Captain Fantastic'.

The 57-year-old actor plays father-of-six Ben who has been raising his kids in a forest cut off from the world following his wife's diagnosis with bipolar disorder.

Viggo and the child actors had to spend weeks undergoing training to prepare for their roles, learning how to do yoga, gut animals and learn how to climb and by the time shooting began they had all developed a close bond leading to him getting the affectionate moniker.

During an appearance on UK TV show 'This Morning', he shared: "It was a very serious period of training, where we did martial arts together and yoga, we had to learn how to guy and skin animals - well some of them, the girls. The rock climbing was pretty adventurous, I have to say it wasn't my favourite thing ... That period of getting ready was wonderful, by the first day of shooting we knew each other really well. They gave me the moniker 'Summer Dad', they anointed me with that, which was a very nice title."

Viggo also had to play the bagpipes in the movie - directed by Matt Ross - as many scenes required the unconventional family to play music together.

However, the 'Lord of the Rings' star admits he never mastered the tricky wind instrument leading to some painful attempts at tunes on set.

He added: "We played a lot of music together. I learned the bag pipes, of a fashion. I think playing the pipes badly is worse than playing any other instrument badly."